The ability of different computer programs to yield accurate peak areas in statistical control in the case of partially overlapping photopeaks has been tested by the Analysis of Precision. A modified Covell method, two commercially available peak-fitting programs from Nuclear Data and Ortec, and the SAMPO80 program were used to evaluate the 843.8 keV peak area in the 843.8/846.6 keV doublet of27Mg and56Mn produced by thermal neutron activation of a candidate biological reference material to be certified for magnesium. The best performance was given by the Ortec program, but a modified SAMPO80 performed almost as well. The modified Covell program gave reliable results, but with poorer precision.